The exemplary embodiment relates to correcting diffusing artifacts from light guide patterning for a multifunction device. While the systems and methods described herein relate to artifact correction, it will be appreciated that the described techniques may find application in other image processing applications.
Xerographic reproduction devices utilize a light source to illuminate a document during copying, scanning, and facsimile operations. The illuminated document may then be reproduced as a digital image, a hardcopy output, or transmitted to a remote location to be output. A light source is used for the illumination of the document, however to fully illuminate the document, the light source may be coupled to a light guide, which directs the light evenly onto the document. Incandescent, halogen, or even fluorescent lamps may be used as the light source, with the light guide directing the output light along the document.
Light emitting diodes (LEDs) may be used as illumination sources. To fully illuminate a document, the LED light is injected into the end of a light guide and a pattern on the light guide is used to change the total internal reflection angle and eject the light at intervals from the light guide. However this pattern remains visible in the structure of the output light. When used in a scanning application it may be possible to calibrate out this non uniformity but if the illumination is not perfectly aligned to the sensor during the scan, as in the case for a full rate/half rate carriage system the pattern becomes visible.
Stated another way, it is highly difficult to utilize LED-based illuminators so as to provide an even illumination along the narrow strip of the document. A light guide uses a pattern to change the total internal reflection angles to eject light at intervals. This pattern in the light guide is not fixed relative to the charge-coupled device (CCD) array and therefore cannot be calibrated out. This pattern may result in an artifact on the output document, i.e., a visible image of the pattern may be depicted on the output document.
Accordingly, there is an unmet need for systems and methods that facilitate removal of light guide pattern artifacts on outputs of multifunction devices.